Florida Center for Advanced Aero-Propulsion, Interdisciplinary Microsystems Group, Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, USA.
J Acoust Soc Am. 2011 Jun;129(6):EL248-53. doi: 10.1121/1.3582150.
Coherence-based analysis techniques utilizing a small number of microphones are often applied in aeroacoustic measurements. These techniques can remove statistically incoherent noise, electronic or hydrodynamic, from acoustic signals measured by microphones, at significantly lower cost than array methods. However, the assumptions involved in the usage of the ordinary coherence function technically limit analysis to a single-source field. In the presence of multiple sources the coherence function breaks down and ordinary analysis techniques under-predict true acoustic levels. This phenomenon is demonstrated mathematically and illustrated using experimental trailing edge noise data.
基于相干性的分析技术通常应用于航空声学测量中，只需要少量麦克风。与阵列方法相比，这些技术可以以更低的成本从麦克风测量的声信号中去除统计上不相关的噪声（电子或流体动力噪声）。然而，普通相干函数的使用假设在技术上限制了分析仅限于单源场。在存在多个声源的情况下，相干函数会失效，普通分析技术会低估真实的声级。这种现象通过数学方法进行了演示，并使用实验的后缘噪声数据进行了说明。
